Apparatus and method for treating a cathode material provided on a thin-film substrate

Abstract

An apparatus and method for treating a cathode material provided on a surface of a continuous thin-film substrate and a treated thin-film cathode having increased smoothness are disclosed. A web of untreated cathode material is moved between a feed mechanism and a take-up mechanism, and passed through a treatment station. The web of cathode material typically includes areas having surface defects, such as prominences extending from the surface of the cathode material. The surface of the cathode material is treated with an abrasive material to reduce the height of the prominences so as to increase an 85 degree gloss value of the cathode material surface by at least approximately 10. The web of cathode material may be subjected to a subsequent abrasive treatment at the same or other treatment station. Burnishing or lapping film is employed at a treatment station to process the cathode material. An abrasive roller may alternatively be used to process the web of cathode material. The apparatus and method of the present invention may also be employed to treat the surface of a lithium anode foil so as to cleanse and reduce the roughness of the anode foil surface.

What we claim is:  
     
       1. A thin-film cathode prepared by a process comprising: 
       providing a thin-film substrate having a coating of cathode material disposed thereon, the cathode material comprising an oxide, conductive carbon, and a binder, some of the cathode material including defects protruding from a surface of the cathode material;  
       moving the thin-film substrate between a feed mechanism and a take-up mechanism; and  
       treating the cathode material surface at a treatment station with an abrasive material to reduce a height of the defects, the cathode material surface of the thin-film cathode having an 85 degree gloss value of at least about 22.  
     
     
       2. The cathode of claim  1 , wherein treating the cathode material surface further comprises moving a film of the abrasive material in a direction substantially opposite to a direction in which the thin-film substrate passes through the treatment station. 
     
     
       3. The cathode of claims  2 , wherein the film of the abrasive material comprises abrasive particles ranging in size between approximately 2 to 60 microns. 
     
     
       4. The cathode of claim  1 , wherein treating the cathode material surface further comprises moving a roller provided with the abrasive material against the cathode material surface, the roller moving in a direction substantially opposite to a direction in which the thin-film substrate passes through the treatment station. 
     
     
       5. The cathode of claim  1 , wherein treating the cathode material surface further comprises: 
       treating the cathode material surface at a first treatment station with a first abrasive material of a first grade; and  
       treating the cathode material surface at a second treatment station with a second abrasive material of a second grade.  
     
     
       6. The cathode of claim  1 , wherein treating the cathode material surface further comprises: 
       treating a surface of the cathode material provided on a first side of the thin-film substrate at a first treatment station; and  
       treating a surface of the cathode material provided on a second side of the thin-film substrate at a second treatment station.  
     
     
       7. The cathode of claim  1 , wherein the height of the defects protruding from the cathode material surface is reduced in height to a height no greater than approximately 10 microns. 
     
     
       8. The cathode of claim  1 , wherein the height of the defects protruding from the cathode material surface is reduced to a height which is less than a thickness of an electrolyte layer to be provided on the cathode material surface. 
     
     
       9. The cathode of claim  1 , wherein the cathode material surface of the thin-film cathode has an 85 degree gloss value of at least about 30. 
     
     
       10. The cathode of claim  1 , wherein the cathode material surface of the thin-film cathode has an 85 degree gloss value of at least about 40. 
     
     
       11. A thin-film cathode prepared by a process comprising: 
       providing a thin-film substrate having a coating of cathode material disposed thereon, the cathode material comprising an oxide, conductive carbon, and a binder, some of the cathode material including defects protruding from a surface of the cathode material;  
       moving the thin-film substrate between a feed mechanism and a take-up mechanism; and  
       treating the cathode material surface at a treatment station with an abrasive material to reduce a height of the defects, the cathode material surface of the thin-film cathode being substantially free of defects having heights of greater than about 19 microns.  
     
     
       12. The cathode of claim  11 , wherein the cathode material surface of the thin-film cathode is substantially free of defects having heights of greater than about 10 microns. 
     
     
       13. The cathode of claim  11 , wherein the cathode material surface of the thin-film cathode is substantially free of defects having heights of greater than about 6 microns. 
     
     
       14. The cathode of claim  11 , wherein the height of the defects protruding from the cathode material surface is reduced to a height which is less than a thickness of an electrolyte layer to be provided on the cathode material surface.